package com.example.fragmentdemo;

import androidx.lifecycle.LifecycleOwner;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModel;

public class MyViewModel extends ViewModel {
    private MutableLiveData<String> data=new MutableLiveData<>();
    private static MyViewModel sInstance;

    public MyViewModel() {
    }


    public static MyViewModel getInstance(){
        if(null==sInstance){
            sInstance=new MyViewModel();
        }
        return sInstance;
    }
//赋值
    public void setData(String str){
        data.postValue(str);
    }
//取值
    public void getStr(LifecycleOwner lo, Observer<String> observer){
        data.observe(lo,observer);
    }
    //移除监听
    public  void removeObserver(Observer<String> observer) {
        data.removeObserver(observer);
    }
}
